Mechanical ventilation assists or replaces spontaneous breathing. Positive pressure ventilation is the provision of air under pressure into the lungs, either invasively or non-invasively. Invasive positive-pressure ventilation is the delivery of positive pressure via an invasive artificial airway, such as an endotracheal tube or tracheostomy tube, while noninvasive positive-pressure ventilation (NPPV) is the delivery of positive pressure without such an invasive artificial airway, instead using a nasal or face mask.
Ventilation modes include volume ventilation, pressure-controlled ventilation, bi-level positive airway pressure (BIPAP) ventilation, inspiratory positive airway pressure (IPAP) ventilation, continuous positive airway pressure (CPAP) ventilation, and pressure-controlled ventilation (PCV). CPAP ventilation delivers a constant pressure, which assists inspiration and resists expiration. BIPAP ventilation delivers a higher pressure during inspiration, and a lower pressure during expiration.